After a five-year investigation, the Serious Fraud Office (SFO) announced on Tuesday that Barclays had been charged with two counts of conspiracy to commit fraud and the provision of unlawful financial assistance.

The charges relate to the bank's move to raise cash from Qatar Holding and Challenger Universal in June and October 2008. They also relate to a $3bn (£2.4bn) loan made available to the State of Qatar in November of that year.

Image:Roger Jenkins left Barclays in 2009

Varley and another senior executive Roger Jenkins were charged with conspiracy to commit fraud by false representation in relation to a first round of investment in June 2008.

Varley and Jenkins have also been charged with another count in regard to a second capital raising in October 2008.

They are also facing a charge of unlawful financial assistance.

Image:Thomas Kalaris formerly ran Barclays Wealth

Two other men in senior roles at the bank in 2008 - Thomas Kalaris and Richard Boath - both face a single charge of conspiracy to commit fraud by false representation in relation to the June 2008 fundraising only.

Varley, who was Barclays chief executive between 2004 and 2011, headed the bank at the time of the deals, while Jenkins, who left the bank in 2009, was investment banking chief.

Kalaris - an American banker living in London - was formerly in charge of the bank's wealth and investment management division, while Boath was the former European head of financial institutions group at Barclays.

Image:Richard Boath says he will contest the charges vigourously

The defendants are due to appear at Westminster Magistrates' Court on 3 July.

A lawyer for Jenkins said he would "vigorously defend" himself against the charges, saying his client had received both internal and external legal advice at the time.

Boath told Sky News he would contest the allegations against him, saying: "The SFO's decision to charge me is based on a false understanding of my role and the facts.

"I was not a decision-maker and had no control over what the bank did in 2008. I repeatedly raised concerns about the decisions taken by the bank with both senior management and senior lawyers and was reassured that those decisions were lawful."

Sky News understands that both Varley and Kalaris plan to plead not guilty too. It was announced later on Tuesday that Varley had stepped down from his role as a senior director of FTSE 100 mining firm Rio Tinto.

Barclays case may show what went on in 2008

The bank said in response that it was "considering its position in relation to these developments" and is awaiting further information about the charges from the SFO.

It added that the City watchdog, the Financial Conduct Authority, had reopened its investigation while US authorities were continuing their own inquiries.

Barclays also reaffirmed it was defending a civil claim against it, brought by PCP Capital Partners and PCP International Finance, in relation to the second capital raising.